1. Field of the Invention
The present invention relates generally to an implantable vascular device and more particularly to an implantable vascular shunt device which would increase the life of a hemodialysis graft and will eliminate problems typical of conventional implantable vascular devices, such as venous thrombosis, high output failure and limb morbidity.
2. Description of the Prior Art
Patients suffering from rental failure are treated by hemodialysis. Hemodialysis is a process wherein a machine is utilize for removal of life-threatening chemicals from the blood stream, since the patient's kidneys cannot successfully remove these chemicals. In order to allow these machines to work, an access to the patients blood flow is required.
Accordingly, a multiplicity of vascular access devices have been designed and implemented which create an artificial fistula between an artery and vein. Typically, these conventional devices are comprised of an graft material that bridges between an artery and vein creating a communication or fistula. One end of the graft is secured to a vessel, such as the device disclosed in U.S. Pat. No. 3,713,441, issued to Thomas. Unfortunately, due to the design and configuration of these devices, such as the one disclosed in Thomas, they are cause prolonged high flow states that can result in damage to the venous wall which leads to occlusion of the vein and thrombosis of the fistula. Due to the high flow state within the veins, these devices can cause several problems other than venous occlusion, such as arterial stenosis, limb swelling and heart failure. When shunt occlusion or thrombosis occurs, another vein segment must be found surgically and a shunt revision performed. The process is repeated at each occurrence of shunt occlusion or thrombosis. Repeated failures will result in complete replacement of the fistula puncturing of the shunt will result failure of the graft material. This process can be extremely costly to the patient and society.
Unfortunately, graft failure is inevitable due to shear forces from high velocity turbulence of blood flow on the venous walls which causes endothelial damage in the form of endothelial hypertrophy (venous wall scaring). Problems that arise from the fistula can limit or hinder the process of hemodialysis, thereby causing severe or fatal consequences to the individual suffering from renal disease.
Accordingly, research has shown that none of these previous efforts provide the benefits intended with the present invention, such as providing a dialysis graft that provides flow rates necessary for dialysis and yet limit the trauma endured by venous walls. Additionally, prior techniques do not suggest the present inventive combination of component elements as disclosed and claimed herein. The present invention achieves its intended purposes, objectives and advantages over the prior art device through a new, useful and unobvious combination of component elements, which is simple to use, with the utilization of a minimum number of functioning parts, at a reasonable cost to manufacture, assemble, and test.